Con Coughlin is the Telegraph's Defence Editor and a world-renowned expert on global security and terrorism issues. He is the author of several critically acclaimed books. His new book, Churchill's First War: Young Winston and the fight against the Taliban, is published by Macmillan in London and Thomas Dunne Books in New York. He appears regularly on radio and television in Britain and America.

The murder of the US ambassador to Libya is a wake-up call for Obama

The murder of the US ambassador and three consulate staff in the Libyan city of Benghazi should act as an urgent wake-up call to President Barack Obama to address America's security concerns properly, rather than trying to avoid them all the time.

Ever since Mr Obama entered the White House he has tried to position himself as a politician who has no interest in getting involved in overseas conflicts. Having withdrawn American forces from Iraq and ordered the withdrawal of US combat troops from Afghanistan by the end of 2014, he has tried to appease his Democrat supporters by making sure that he steered well clear of involvement in any of the world's other trouble spots.

On crucial security issues such as Iran, Libya and Syria he has deliberately taken a back seat, rather than providing the strong and effective leadership the world has come to expect from a major superpower. As a result a dangerous power vacuum has been created with those, such as the group responsible for the well-planned attack on the American consulate in Benghazi, believing they can act with impunity.

But with the American presidential election only two months away, the murder of four American diplomats could be a game changer so far as Mr Obama's re-election prospects are concerned.

During the 2008 contest Hillary Clinton, Mr Obama's main rival for the Democratic nomination, used to tease him about the "red telephone moment", when the president is awoken in the middle of the night to deal with an international crisis. Mr Obama would have received that call last night and how he responds to it could ultimately decide the outcome of the election.

Mr Obama likes to portray himself as a cool, hip and media -riendly president. But the job demands much more than that, and unless he is careful Mr Obama will end up being viewed like his Democratic predecessor President Jimmy Carter, another well-meaning do-gooder, who was eventually exposed as weak and ineffectual, and paid for it by being unceremoniously dumped out of office by the great American public.

Unless he starts to provide strong leadership and gets a firm grip on national security, Mr Obama will suffer the same fate.